Rewrite grid-line production with range notation

Author: cdoublev

css-grid-1/Overview.bs

@@ -2959,7 +2959,7 @@ Line-based Placement: the 'grid-row-start', 'grid-column-start', 'grid-row-end',
 		<dfn for="grid-row-start, grid-column-start, grid-row-end, grid-column-end"><<grid-line>></dfn> =
 		  auto |
 		  <<custom-ident>> |
-		  [ <<integer>> && <<custom-ident>>? ] |
+		  [ [ <<integer [∞,-1]>> | <<integer [1,∞]>> ] && <<custom-ident>>? ] |
 		  [ span &amp;&amp; [ <<integer [1,∞]>> || <<custom-ident>> ] ]
 	</pre>
 
@@ -2985,7 +2985,7 @@ Line-based Placement: the 'grid-row-start', 'grid-column-start', 'grid-row-end',
 			Otherwise,
 			treat this as if the integer ''1'' had been specified along with the <<custom-ident>>.
 
-		<dt><dfn id='grid-placement-int'><<integer>> && <<custom-ident>>?</dfn>
+		<dt><dfn id='grid-placement-int'>[ <<integer [∞,-1]>> | <<integer [1,∞]>> ] && <<custom-ident>>?</dfn>
 		<dd>
 			Contributes the <var>N</var>th <a>grid line</a> to the <a>grid item</a>’s <a>placement</a>.
 			If a negative integer is given,

css-grid-2/Overview.bs

@@ -3103,7 +3103,7 @@ Line-based Placement: the 'grid-row-start', 'grid-column-start', 'grid-row-end',
 		<dfn for="grid-row-start, grid-column-start, grid-row-end, grid-column-end"><<grid-line>></dfn> =
 		  auto |
 		  <<custom-ident>> |
-		  [ <<integer>> && <<custom-ident>>? ] |
+		  [ [ <<integer [∞,-1]>> | <<integer [1,∞]>> ] && <<custom-ident>>? ] |
 		  [ span &amp;&amp; [ <<integer [1,∞]>> || <<custom-ident>> ] ]
 	</pre>
 
@@ -3129,7 +3129,7 @@ Line-based Placement: the 'grid-row-start', 'grid-column-start', 'grid-row-end',
 			Otherwise,
 			treat this as if the integer ''1'' had been specified along with the <<custom-ident>>.
 
-		<dt><dfn id='grid-placement-int'><<integer>> && <<custom-ident>>?</dfn>
+		<dt><dfn id='grid-placement-int'>[ <<integer [∞,-1]>> | <<integer [1,∞]>> ] && <<custom-ident>>?</dfn>
 		<dd>
 			Contributes the <var>N</var>th <a>grid line</a> to the <a>grid item</a>’s <a>placement</a>.
 			If a negative integer is given,